I stumbled upon this when I was craving apple crisp, but had only 30 minutes before dinner. We've been having this A LOT lately because all four of us love it AND it is easy. I've tweaked it to fit our tastes. We actually use it as a side dish rather than a dessert.
First off, I insist that you invest in one of these babies to aide in your quest to "keep it simple". I peeled, sliced, and cored a dozen apples in about 10 minutes, and this 10 minutes included dealing with a 3 year old who wanted to help, insisting she could do it herself.
8 cups of peeled, cored, and sliced tart apples (I used a dozen small apples)
3/4 c packed brown sugar (divided)
1/2 c flour (divided)
1 c quick cooking oats
1/2 c cold butter
Toss apples with 1/4 c of the brown sugar and 2 tbl of flour and cinnamon (to taste); place in microwave safe casserole dish (sprayed with cooking spray).
In a bowl, combine oats, remaining brown sugar and flour, and more cinnamon (to taste). Cut in butter until crumbly. Sprinkle over apple mixture.
Cover with plastic wrap, leaving a corner open to vent. Microwave on high for 10 minutes or until apples are tender.
Note: the topping will not be "crisp". It is more ooey gooey! (I always eat the leftovers for breakfast the next day)